feat: add termination parameter to ChatAgent step and astep

camel/agents/chat_agent.py

@@ -564,10 +564,13 @@ async def _aformat_response_if_needed(
             message.content = response.output_messages[0].content
             self._try_format_message(message, response_format)
 
+    import threading
+
     def step(
         self,
         input_message: Union[BaseMessage, str],
         response_format: Optional[Type[BaseModel]] = None,
+        stop_event: Optional[threading.Event] = None,
     ) -> ChatAgentResponse:
         r"""Executes a single step in the chat session, generating a response
         to the input message.
@@ -580,6 +583,9 @@ def step(
                 model defining the expected structure of the response. Used to
                 generate a structured response if provided. (default:
                 :obj:`None`)
+            stop_event (Optional[threading.Event], optional): Event to signal
+                termination of the agent's operation. When set, the agent will
+                terminate its execution. (default: :obj:`None`)
 
         Returns:
             ChatAgentResponse: Contains output messages, a termination status
@@ -613,6 +619,13 @@ def step(
                 self._get_full_tool_schemas(),
             )
 
+            # Terminate Agent if stop_event is set
+            if stop_event and stop_event.is_set():
+                # Use the _step_token_exceed to terminate the agent with reason
+                return self._step_token_exceed(
+                    num_tokens, tool_call_records, "termination_triggered"
+                )
+
             if tool_call_requests := response.tool_call_requests:
                 # Process all tool calls
                 for tool_call_request in tool_call_requests:
@@ -659,6 +672,7 @@ async def astep(
         self,
         input_message: Union[BaseMessage, str],
         response_format: Optional[Type[BaseModel]] = None,
+        stop_event: Optional[threading.Event] = None,
     ) -> ChatAgentResponse:
         r"""Performs a single step in the chat session by generating a response
         to the input message. This agent step can call async function calls.
@@ -675,6 +689,9 @@ async def astep(
                 used to generate a structured response by LLM. This schema
                 helps in defining the expected output format. (default:
                 :obj:`None`)
+            stop_event (Optional[threading.Event], optional): Event to signal
+                termination of the agent's operation. When set, the agent will
+                terminate its execution. (default: :obj:`None`)
 
         Returns:
             ChatAgentResponse: A struct containing the output messages,
@@ -705,6 +722,13 @@ async def astep(
                 self._get_full_tool_schemas(),
             )
 
+            # Terminate Agent if stop_event is set
+            if stop_event and stop_event.is_set():
+                # Use the _step_token_exceed to terminate the agent with reason
+                return self._step_token_exceed(
+                    num_tokens, tool_call_records, "termination_triggered"
+                )
+
             if tool_call_requests := response.tool_call_requests:
                 # Process all tool calls
                 for tool_call_request in tool_call_requests:

camel/responses/agent_responses.py

@@ -39,8 +39,5 @@ class ChatAgentResponse(BaseModel):
     @property
     def msg(self):
         if len(self.msgs) != 1:
-            raise RuntimeError(
-                "Property msg is only available "
-                "for a single message in msgs."
-            )
+            return None
         return self.msgs[0]